If you go out and about and draw, or if you plan to take a subset of your pen collection on your travels, you will need a method of transporting your drawing tools. For many years, I used a heavy duty Zip-Lok baggie to carry pens & markers in my backpack. It works. You can see your pens and grab just the right color. But as I drew more I wanted my pens to have a space of their own. Is a pen case a luxury? I suppose so.